Swim from Grand Portage Minnesota to Isle Royal Michigan

I am planning a 18 mile swim in Lake Superior from Grand Portage to Isle Royal. I was wonder if anyone has done this swim before? I am going to have an escort boat and planning on camping on the Island possibly swimming back. any input would be helpful!

I live in Minnesota and my husband and his father have been camping on Isle Royal and enjoyed it. Also the history of Lake Superior and all the mystery that is in such a large lake. The water temp will be low high 50's low 60's.